Cumberland County Average 1999 NATA Modeled Air Concentrations Compared to Health Benchmarks

Pollutant

Modeled
Air Concentration (ug/m3)

Health
Benchmark (ug/m3)

Risk
Ratio

%
Contribution from

Major Sources

Area
Sources

On-road
Mobile Sources

Nonroad
Mobile Sources

Background

Acetaldehyde

1

0.45

2

0.9%

3%

29%

17%

51%

Acrolein

0.05

0.020

2

3%

19%

47%

32%

0%

Arsenic Compounds

0.0001

0.00023

0.4

66%

34%

0%

0%

0%

Benzene

0.9

0.13

7

0.7%

6%

29%

20%

44%

Bis(2-ethylhexyl)phthalate

2

0.42

4

0.0003%

0%

0%

0%

100%

1,3-Butadiene

0.07

0.033

2

0.2%

2%

34%

15%

49%

Cadmium Compounds

0.00004

0.00024

0.2

39%

61%

0%

0.3%

0%

Carbon Tetrachloride

0.3

0.067

4

0%

0.1%

0%

0%

100%

Chloroform

0.05

0.043

1.2

0.4%

21%

0%

0%

78%

Chromium (hexavalent form)

0.00006

0.000083

0.7

7%

86%

7%

0.6%

0%

1,4-Dichlorobenzene

0.02

0.091

0.3

2%

98%

0%

0%

0%

1,3-Dichloropropene

0.05

0.25

0.2

0.001%

100%

0%

0%

0%

Diesel Particulate Matter

1

0.0033

369

0%

0%

43%

57%

*

Ethylene Dibromide

0.02

0.0017

11

0%

0.001%

0%

0%

100%

Ethylene Dichloride

0.03

0.038

0.9

0.2%

0.4%

0%

0%

99%

Ethylene Oxide

0.002

0.011

0.1

9%

91%

0%

0%

0%

Formaldehyde

1

0.077

14

0.8%

4%

20%

11%

65%

Methyl Chloride

1

0.56

2

0.2%

0.3%

0%

0%

100%

Naphthalene

0.03

0.029

0.9

4%

64%

26%

6%

0%

Nickel Compounds

0.0007

0.0064

0.1

59%

34%

2%

4%

0%

Perchloroethylene

0.1

0.17

0.7

0.004%

31%

0%

0%

69%

1,1,2,2-Tetrachloroethane

0.05

0.017

3

0%

0.2%

0%

0%

100%

Chemicals with risk ratios greater than or equal to 1 are
in bold.
Risk Ratios in italics are based on noncarcinogenic effects.
The seymbol ug/m3 is micrograms per cubic meter,
the amount (in micrograms) of a chemical in a cubic
meter of air. This is also known as a concentration.
* For diesel particulate matter, onroad and nonroad
concentrations include a model-estimated background
concentration.